<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=<device-width>, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script>
    </script>
</head>
<body>
    <div id="div1">haha</div>
</body>
<script>
var title = 'hi'
var obj = {
    title: 'hello',
    show1: function() {
        console.log(this.title)
    },
    show2: function() {
        show()
    },
    show3: function() {
        return function() {
            return this.title
        }
    },
    show4: () => {
        return this.title
    }
}
function show() {
    console.log(this.title)
}
obj.show1()
obj.show2()
var s = obj.show3()
console.log(s())
console.log(s.call(obj))
console.log(obj.show4())
</script>
</html>